Inventions of the World
Alexander.
Graham Bell
(Date unknown)
Bell telephone. Historical artwork of a man using a Bell telephone. In this original telephone system, the speaker and receiver were identical. The speaker consisted of a diaphragm which converted sound waves into an oscillating electric current. The receiver converted the current back into sound waves. This telephone was invented by Alexander Graham Bell (1847-1922) who filed the patent in 1876. However, his priority as absolute inventor was questioned by Elisha Gray of Western Electric who similarly filed a patent on the same day, 14th February. After long litigation, Bell won 'the most valuable patent ever issued in the US'.